Method of reducing hydrophobic contaminants in a pulping or papermaking process

ABSTRACT

A method of reducing contaminants in a pulp or papermaking process includes the steps of:
         providing a lignocellulosic pulp comprising lignocellulosic fibers and at least one hydrophobic contaminant;   providing a cationic polymer; providing a cleaning blend comprising a vegetable oil alkyl ester and at least one surfactant; and   applying the cationic polymer and the cleaning blend to the lignocellulosic pulp to reduce a content of the at least one hydrophobic contaminant in the pulp or papermaking process.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/260,737, filed Aug. 31, 2021, and U.S. Provisional Application No. 63/364,635, filed May 13, 2022, each of which is expressly incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure generally relates to a method of reducing hydrophobic contaminants in a pulping or papermaking process. More specifically, this disclosure relates to applying a cationic polymer and a particular cleaning blend to the lignocellulosic pulp to reduce a content of hydrophobic contaminants in a pulping or papermaking process.

BACKGROUND

The processing of wood and other biomass materials to form pulp results in the release of hydrophobic plant materials commonly described as “pitch” into a process liquor. Pitch is typically described as a natural wood component (2-6% of raw wood) that gets liberated from lignocellulosic fiber upon wood chip pulping. The hydrophobic plant materials are soluble in organic solvents and can be quantified by extracting dry wood or pulp mass and evaporating the solvent. An “extractives content” is defined as a weight fraction of extracted material versus a starting material after extraction with a designated solvent or solvents, as described in TAPPI Standard T 204 cm-17 Solvent Extractives of Wood and Pulp. The mixtures of hydrophobic plant materials and solvents may be further analyzed using gas chromatography and mass spectrometry GC-MS to identify individual substances. Standard laboratory GC methods with Flame Ionization Detection GC-FID may be calibrated with standards to quantify selected compounds and to group similar substances into classes based on structures, functional groups, etc. The method may be used to estimate the quantity of each “class” in a pitch sample.

These hydrophobic plant materials diffuse out of wood in small colloidal form during hot pulp cooking and defiberization processes and may continue to diffuse throughout washing, oxygen delignification, bleaching, and extraction stages if the pulp is bleached in further processing. As the pulp undergoes these stages, washing is often performed therebetween. The hydrophobic plant materials may be partially removed with the wash liquor and may partially remain fixed to the lignocellulosic fibers. The hydrophobic plant materials may also separate from the lignocellulosic fibers during drying, e.g. if a mat is dried for repulping later, as water is driven out. The hydrophobic plant materials may then deposit on equipment surfaces and dryer felt. The hydrophobic plant materials may also diffuse out of the lignocellulosic fibers much later, e.g. when the lignocellulosic fibers are formed into a mat and dewatered to form paper in various types of paper mills. These types of hydrophobic plant materials may deposit on equipment or paper anywhere in a papermaking process from pulp storage tanks to a final dried sheet.

Agglomeration of the small colloidal particles of the hydrophobic plant materials into larger particles is a probable mechanism for pitch deposition, among others. Changes in process environments may encourage agglomeration. These changes may include changes in temperature, pH of aqueous fiber slurries, a presence of added surfaces favorable for deposition, agitation, and vibration, among others.

Natural pitch can form undesirable deposits anywhere and at any time during pulping processes, pulp bleaching, storage and later in the papermaking process. Pitch deposits can be troublesome for the process equipment, plugging wash screens, press and dryer felts, and thus requiring maintenance downtime. More importantly, if allowed to agglomerate and form larger deposits, pitch manifests as visible flaws in the pulp sheet and downgrades product quality. Defects from pitch deposition are not desirable and will lead to direct financial losses.

Various approaches of controlling hydrophobic plant materials are based on application of detackification agents which can coat pitch particles and make them less hydrophobic and less tacky. This can be achieved by application of specific polymers of a dual nature (e.g. hydrophobically modified polyethylene glycols, hydrophobically modified polyaminoamides or hydrophobically modified cellulose derivatives). Alternatively, controlling hydrophobic plant materials can include using inorganic minerals, e.g. talc. Natural mineral talc has been used as an effective pitch control agent for many years. Talc microscopic platelets, being hydrophobic in nature, can easily interact with and coat pitch particles and make them less tacky. Talc coated pitch particles can then be incorporated with lignocellulosic fibers adding to the overall pulp yield. However, there is a commercial desire to move away from talc. Other minerals such as bentonite, kaolin, smectite, and others and/or modified minerals have also been used for pitch control.

There are challenges in talc applications related to an inconvenience of using powdered material in general which requires special makedown units. Also, talc abrasiveness limits its use in pulp preparations for tissue and towel applications were bulk and softness are of great importance.

Pitch control agents with different modes of action are not commonly used together. In many cases, such agents are not compatible with each other and, in some cases, have opposing functionalities. For example, application of fixatives leads to removal of organic contaminant from dissolved/colloidal phases onto the surface of lignocellulosic fibers. On the other hand, application of cleaning agents leads to solubilization and dissolution of tacky deposits from the equipment surface to an aqueous phase. Accordingly, there remains opportunity for improvement.

BRIEF SUMMARY

This disclosure provides a method of reducing hydrophobic contaminants in a pulping or papermaking process. The method includes the steps of:

-   -   providing a lignocellulosic pulp comprising lignocellulosic         fibers and at least one hydrophobic contaminant;     -   providing a cationic polymer;     -   providing a cleaning blend comprising a vegetable oil alkyl         ester and at least one surfactant; and     -   applying the cationic polymer and the cleaning blend to the         lignocellulosic pulp to reduce a content of the at least one         hydrophobic contaminant in the pulping or papermaking process.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and

FIG. 1 is a bar graph showing % pitch particle count reduction as a function of Polymers and Formulations of the Examples;

FIG. 2 is a bar graph showing % pitch particle count reduction as a function of Formulation of the Examples;

FIG. 3 is a bar graph showing pitch particle count as a function of Formulation of the Examples;

FIG. 4 is a bar graph showing % pitch particle count reduction as a function of Polymer and Formulation of the Examples;

FIG. 5 is a bar graph showing % pitch particle count reduction as a function of Polymer and Formulation of Example 4;

FIG. 6 is a bar graph showing % pitch particle count reduction as a function of Polymer and Formulation of Example 5; and

FIG. 7 is a bar graph showing % pitch particle count reduction as a function of Polymer and Formulation of Example 6.

FIG. 8 is a bar graph showing % pitch particle count reduction as a function of polymer and formulation dosages and their separate or combined application

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the instant method. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

Various embodiments of the present disclosure are generally directed to hydrophobic contaminant control compositions and methods for forming and using the same. For the sake of brevity, conventional techniques related to hydrophobic contaminant removal in lignocellulosic pulp may not be described in detail herein. Moreover, the various tasks and process steps described herein may be incorporated into a more comprehensive procedure or process having additional steps or functionality not described in detail herein. In particular, various steps in the manufacture of pulp compositions are well-known and so, in the interest of brevity, many conventional steps will only be mentioned briefly herein or will be omitted entirely without providing the well-known process details. In this disclosure, the terminology “about” can describe values ±0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10%, in various embodiments. Moreover, it is contemplated that, in various non-limiting embodiments, all values set forth herein may be alternatively described as approximate or “about.” It is also contemplated that the terminology weight percent described anywhere herein may be further described as weight percent actives, as would be understood by one of skill in the art. As just one non-limiting example, this weight percent actives may be based on a total weight of actives of a combination of the cationic polymer and the cleaning blend.

The current disclosure describes efficient alternatives for pitch removal from various processes including pulping processes. The method may include using formulations in which cationic polymers (such as fixatives) are combined with dispersing and/or cleaning and/or passivation agents. Different classes of compounds can be used for pitch control or pitch deposition issues remediation due to their detackifying, passivating, dissolving and stabilization properties.

As is appreciated in the art, the terminology detackification typically means interaction with hydrophobic particles and making them less tacky and less prone to agglomeration and deposition. The terminology passivation and stabilization typically mean interaction with equipment surfaces and coating them with passivation layer or making them more stable by changing their surface characteristics and less prone to deposition. Cleaning agents are typically solvents or solvents combined with surfactants and are typically used to solubilize and clean organic deposits from equipment surfaces.

It has been unexpectedly found that combining selected fixatives and selected passivating, dissolving and stabilization agents/treatments may lead to a synergistic increase in pitch control properties. More specifically, in various embodiments, by combining high charge cationic acrylamide emulsions with a combination of vegetable oil methyl ester and non-ionic surfactant(s), and optionally vegetable oil, pitch control effect is unexpectedly higher than the effect of individual components.

In various embodiments, this technology is utilized to reduce or eliminate agglomeration of pitch particles and reduce, remove, or eliminate pitch deposition, in various processes as chosen by one of skill in the art. For example, this technology is typically utilized to reduce or eliminate agglomeration of pitch particles and reduce, remove or eliminate pitch deposition. It can be applied in a pulp setting and/or a paper machine. This technology can be effectively applied for pitch control when virgin pulp or TMP, NSSC, deinked, or other pulps are used in papermaking. This technology can also be used for stickies control as well in recycled mills with the use of OCC pulp or blends of OCC with virgin pulp, deinked pulp, MOW, NSSC, TMP of other source of pulp.

This disclosure provides a method of reducing hydrophobic contaminants in a pulping or papermaking process. In various embodiments, this method provides a cleaner overall pulping or papermaking process and system. For example, if water is recycled, pitch particles are greatly reduced or eliminated such that they do not re-enter the overall process.

The method may include, consist essentially of, or consist of, the steps of: providing a lignocellulosic pulp comprising lignocellulosic fibers and at least one hydrophobic contaminant; providing a cationic polymer; providing a cleaning blend comprising a vegetable oil alkyl ester and at least one surfactant and optionally vegetable oil; and applying the cationic polymer and the cleaning blend to the lignocellulosic pulp to reduce a content of the at least one hydrophobic contaminant in the pulping or papermaking process. The terminology “consist essentially of” may describe various embodiments that are free of one or more steps of utilizing components that are not described herein and/or are described as optional herein.

The method includes the step of providing the lignocellulosic pulp which includes the lignocellulosic fibers and which includes the at least one hydrophobic contaminant. Relative to the lignocellulosic pulp, this pulp includes one or more types of lignocellulosic fibers which may be alternative described as “fibers” herein. These lignocellulosic fibers may be derived from any source known in the art. In various embodiments, the lignocellulosic fibers are derived from virgin fiber, NSSC pulp, mechanical pulp, thermomechanical pulp, unbleached Kraft pulp, deinked pulp, OCC pulp, recycled paper or cardboard, or combinations thereof. The weight or amount of the lignocellulosic fibers in the pulp is not particularly limited and may be chosen by one of skill in the art. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

Referring back to the at least one hydrophobic contaminant, the at least one hydrophobic contaminant may be any known in the art of papermaking and/or pulp processing. In various embodiments, the at least one hydrophobic contaminant is a hydrophobic plant material. In other embodiments, the at least one hydrophobic contaminant is hydrophobic pitch. Alternatively, the at least one hydrophobic contaminant may be what is known in the art as a “stickie” mostly originated from recycle pulp. Pitch is a combination of fatty acids, resin acids, fatty acid triglycerides, long chain fatty alcohols, sterols and combinations thereof.

The weight or amount of the at least one hydrophobic contaminant is not particularly limited and may be chosen by one of skill in the art. However, the at least one hydrophobic contaminant is typically present in the pulp in an amount of from about 0 to about 0.001%, about 0.05% to about 0.1%, or about 0.5% to about 1.0%, weight percent actives based on a total weight of the pulp. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

In one embodiment, the method also includes the step of providing a contaminant control composition, alternatively described herein as the “composition.” The composition typically is, includes, consists essentially of, or consists of a cationic polymer and a cleaning blend. The weight or amount of the cationic polymer and the cleaning blend are not particularly limited and may be chosen by one of skill in the art. Various weights are described in detail below. The terminology “consist essentially of” may describe various embodiments that are free of, or include less than about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 wt %, of other cationic polymers that are not the cationic polymer of this disclosure and/or one or more ethers, esters, alkoxylates, surfactants, additives, etc. that are not those described herein or are optional herein.

The composition is not particularly limited and may be a liquid or may be an aqueous or non-aqueous emulsion. The emulsion is also not particularly limited and may be further described as an oil-in-water emulsion, a water-in-oil emulsion, a water-in-oil-in-water emulsion, or an oil-in-water-in-oil emulsion.

Alternatively, the method may be described as including the steps of providing the cationic polymer and the providing the cleaning blend. The cationic polymer and the cleaning blend may be provided separately or together.

Referring specifically to the cationic polymer, this polymer may be any known in the art. The cationic polymer can interact with negatively charged pitch particles and also interact with negatively charged surfaces of lignocellulosic fibers. As a result of those interactions, hydrophobic pitch particles can get fixated on the surface of lignocellulosic fibers. The cationic polymer can be alternatively described as a fixative.

In various embodiments, the cationic polymer is chosen from cationic polyacrylamides, polyvinylamines, polyethyleneimines, diallyldimethylammonium chloride polymers, trialkylamminoalkyl (meth)acrylamide polymers, epichlorohydrin-dimethylamine copolymers, and combinations thereof Alternatively, the cationic polymer may be chosen from polydiallyldimethylammonium chloride, polyamines, polyvinylamines, cationic polyacrylamides, copolymers of polydiallyldimethylammonium chloride and acrylic acid, and combinations thereof

Alternatively, the cationic polymer may be a cationic polyacrylamide. In various embodiments, the cationic polyacrylamide is a copolymer of a cationic monomer and acrylamide. The cationic monomers may include, for example but without limitation: N,N-dialkylaminoalkyl(meth)acrylates, such as N,N-dimethylaminoethylacrylate and N,N-dimethylaminoethylmethacrylate, or N,N-dialkylaminoalkyl(meth)acrylamides, such as N,N-dimethylaminopropylacrylamide, N,N-dimethylaminopropylmethacrylamide, and/or the salts and quaternaries thereof; and/or combinations thereof

In various embodiments, the cationic polymer is cationic polyacrylamide where the molar content of the cationic monomer relative to the total monomer is from about 15 mole % to about 50 mole %. In various embodiments, this amount is from about 20 to about 45, about 25 to about 40, or about 30 to about 35, mole %. In one embodiment, the cationic polymer is 30 mol %. Polymer weight average molecular weight may be from about 0.1 mln to about 10.0 mln Da, or from about 0.5 mln to about 2.0 mln Da. In various embodiments, this molecular weight is about 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2, mln Da. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

In various embodiments, the most efficient polymers may be or include highly charged cationic polyacrylamides. The cationic acrylamide can be in the form of non-aqueous or aqueous emulsion or a powder.

In one embodiment, the cationic polymer is polydiallyldimethylammonium chloride (PolyDADMAC). In various embodiments, the specific PolyDADMAC has a weight average molecular weight (Mw) of from about 100,000 to about 500,000 Da. In another embodiment, the cationic polymer is a polyamine. The type of polyamine is not particularly limited and may be chosen by one of skill in the art, having a weight average molecular weight Mw of from about 100,000 to about 500,000 Da. In another embodiment, the cationic polymer is a polyvinylamine. For example, the polyvinylamine may be derived from at least one monomer chosen from N-vinylformamide, N-vinyl methyl formamide, N-vinylphthalimide, N-vinyl succinimide, N-vinyl-t-butylcarbamate, N-vinylacetamide, and mixtures of any of the foregoing, wherein typically at least one monomer is N-vinylformamide having a weight average molecular weight Mw of from about 300,000 to about 500,000 Da. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

In another embodiment, the cationic polymer is a polymer dispersion including (i) a high molecular weight cationic polyacrylamide and (ii) a low molecular weight highly changed cationic dispersant polymer.

In another embodiment, the cationic polymer is a cationic polyacrylamide. The type of cationic polyacrylamide is not particularly limited and may be chosen by one of skill in the art and may be as described above.

Alternatively, the cationic polyacrylamide may be derived from at least one monomer chosen from diallyldimethylammonium chloride, N,N,N-trialkylamminoalkyl (meth)acrylate, N,N,N-trialkylamminoalkyl (meth) acrylamide, epichlorohydrin-dimethylamine and combinations thereof.

In yet another embodiment, the weight average molecular weight of the cationic polymer is from about 100,000 to about 10 million Da and e.g. about 400,000 to about 1 million Da. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

In various embodiments, the cationic polymer is present in an amount of from about 1 to about 90, about 10 to about 90, about 16 to about 84, about 20 to about 80, about 25 to about 75, about 30 to about 70, about 35 to about 65, about 40 to about 60, about 45 to about 55, or about 50 to about 55, weight percent actives based on a total weight of the actives of all components in the composition, e.g. the cationic polymer, the vegetable oil alkyl ester and the at least one surfactant and optionally vegetable oil. Alteratively, the weight basis may be weight percent actives based on a total weight of actives of a combination of the cationic polymer and the cleaning blend. In one embodiment, the cationic polymer is present in an amount of from about 1 to about 51 weight percent actives based on a total weight of actives of a combination of the cationic polymer and the cleaning blend. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

In other embodiments, the weight ratio of actives of the cationic polymer to the cleaning blend is from about 20 to about 80, about 25 to about 75, about 30 to about 70, about 35 to about 65, about 40 to about 60, about 45 to about 55, or about 50 to about 55. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

Referring now to the cleaning blend itself, this composition may be, include, consist essentially of, or consists of, a vegetable oil alkyl ester and at least one surfactant and optionally vegetable oil. The terminology “consist essentially of” may describe various embodiments that are free of, or include less than about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 wt %, of other compounds that are not the vegetable oil alkyl ester and/or at least one surfactant of this disclosure and/or the optional vegetable oil and/or one or more ethers, esters, alkoxylates, surfactants, additives, etc. that are not those described herein or are described as optional herein. The weight or amounts of the vegetable oil alkyl ester, optional vegetable oil, and/or at least one surfactant are not particularly limited and may be chosen by one of skill in the art.

In various embodiments, the cleaning blend is typically present in an amount of from about 0 to about 1, about 30 to about 50, or about 70 to about 90, or about 90 to about 99 weight percent actives based on a total weight of actives of the combination of the cationic polymer, the ester and the surfactant, and the optional vegetable oil or based on a total weight of actives of, or a total weight of, the composition. In other embodiments, this amount is about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 . . . up to about 99.9, weight percent actives based on a total weight of actives of the combination of the cationic polymer, the ester and the surfactant, and the optional vegetable oil or based on a total weight of actives of, or a total weight of, the composition. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

The vegetable oil alkyl ester is not particularly limited in type and may be any known in the art. In various embodiments, the vegetable oil alkyl ester is chosen from soybean oil methyl esters, canola (rapeseed) oil methyl esters, corn oil methyl esters, castor oil methyl esters, and combinations thereof. In other embodiments, the vegetable oil alkyl ester is soybean oil methyl ester.

In various embodiments, the vegetable oil alkyl ester is present in an amount of from about 0.5 to about 1.0, about 5.0 to about 10.0, or about 50 to about 90, weight percent actives based on a total weight of actives of the combination of the cationic polymer, the ester and the surfactant, and the optional vegetable oil or based on a total weight of actives of, or a total weight of, the composition. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

The optional vegetable oil is not particularly limited in type and may be any known in the art. In various embodiments, the optional vegetable oil is chosen from soybean oil, canola (rapeseed) oil, corn oil, coconut oil, olive oil, palm oil, castor oil, and combinations thereof. In various embodiments, the optional vegetable oil is soybean oil.

In other embodiments, the optional vegetable oil is typically present in an amount of from about 0.025 to about 0.5, about 1.0 to about 5.0, or about 10.0 to about 25, weight percent actives based on a total weight of actives of the combination of the cationic polymer, the ester and the surfactant, and the optional vegetable oil or based on a total weight of actives of, or a total weight of, the composition. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

It is also contemplated that, in addition to, or as a substitute for, the optional vegetable oil, one or more hydrophobic agents can be utilized. For example, the hydrophobic agent may be chosen from animal oils, mineral oils, silicone oils, terpenes, natural and synthetic aliphatic hydrocarbons, and combinations thereof. In various embodiments, the one or more hydrophobic agents may be present in an amount of from about 0.025 to about 0.5, about 1.0 to about 10.0, or about 50.0 to about 90.0, weight percent actives based on a total weight of actives of the combination of the cationic polymer, the ester and the surfactant, and the optional vegetable oil or based on a total weight of actives of, or a total weight of, the composition. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

The at least one surfactant is not particularly limited in type and may be any known in the art. In various embodiments, the at least one surfactant is chosen from cationic surfactants, anionic surfactants, non-ionic surfactants, zwitterionic surfactants, amphoteric surfactants, and combinations thereof. In other embodiments, the at least one surfactant is chosen from linear ethoxylated alcohols, branched ethoxylated alcohols, ethoxylated fatty acids, ethoxylated castor oils, ethoxylated sorbitan alcohols, alkyl polyglucosides, ethoxylated glycerides, copolymers of ethylene oxide and propylene oxide, and combinations thereof.

In various embodiments, the at least one surfactant is an ethoxylated castor oil. For example, the at least one surfactant may be an ethoxylated castor oil ethoxylated with 13 to 42 moles of ethylene oxide. Alternatively, the at least one surfactant may also include, but is not limited to, C12-C18 alcohol ethoxylates and/or fatty alcohol ethoxylates with about 3 to about 20 EO units. Alternatively, the at least one surfactant is a non-ionic surfactant. Alternatively, the at least one surfactant is or includes a high HLB surfactant, e.g. having an HLB of from about 8 to about 16.

In other embodiments, the at least one surfactant is present in an amount of from, about 0.5 to about 1.0, about 5.0 to about 10.0, or about 30 to about 50, of from about 0.5 to about 90, about 1 to about 90, about 5 to about 90, about 10 to about 90, about 30 to about 90, about 50 to about 90, about 5 to about 85, about 10 to about 80, about 15 to about 75, about 20 to about 70, about 25 to about 65, about 30 to about 60, about 35 to about 55, about 40 to about 50, about 45 to about 50, or about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90, weight percent actives based on a total weight of actives of the combination of the cationic polymer, the ester and the surfactant, and the optional vegetable oil or based on a total weight of actives of, or a total weight of, the composition or weight percent actives based on a total weight of actives of the combination of the cationic polymer, the ester and the surfactant, and the optional vegetable oil or based on a total weight of actives of, or a total weight of, the composition. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

In various embodiments, a relative ratio of vegetable oil methyl ester, optional vegetable oil and surfactant(s) can vary broadly, wherein the amount of each component can vary from about 20 to about 80% for the vegetable oil methyl ester, about 0 and up to about 20% for the optional vegetable oil , and about 20 to about 80%, for the at least one surfactant. More specifically, the weight amounts can be from about 40 to about 60% for the vegetable oil methyl ester, about 0 and up to about 20% for the optional vegetable oil and from about 40 to about 60% for the at least one surfactant.

In various embodiments, the % weight ratio of actives of cationic polymer and a cleaning blend can vary from about 5:1, about 2:1, about 1:1, or about 1:2 to about 1:5. In various embodiments, the weight ratio of actives of cationic polyacrylamide to the cleaning blend is from about 1:1 to about 1:5. If expressed in %, in various embodiments, the cationic polymer is present in an amount of about 16 to about 50 wt % actives and the cleaning blend is present in an amount of from about 50 to about 84% actives, based on a total weight of the cationic polymer and the cleaning blend.

The method also includes the step of applying the cationic polymer and the cleaning blend, or alternatively, applying the contaminant control composition, to the lignocellulosic pulp to reduce a content of the at least one hydrophobic contaminant in the pulping or papermaking process. The step of applying may occur at any point in any papermaking process or any pulp mill process. In one embodiment, the step of applying the contaminant control composition to the pulp is further defined as applying the contaminant control composition to the pulp in a pulp mill. In another embodiment, the step of applying the contaminant control composition to the pulp is further defined as applying the contaminant control composition to the pulp in a papermaking machine.

Alternatively, the step of applying the cationic polymer and the step of applying the cleaning blend to the pulp is further defined as applying to the pulp in a pulp mill. In another embodiment, the step of applying the cationic polymer and the step of applying the cleaning blend to the pulp is further defined as applying in a papermaking machine.

In one embodiment, the cationic polymer is applied to the lignocellulosic pulp simultaneously (which may mean applied at the same time but separately from each other or applied at the same time when together as a blend or mixture) with the cleaning blend. In another embodiment, the cationic polymer is applied to the lignocellulosic pulp independently from the cleaning blend. The step of applying the cationic polymer and the step of applying the cleaning blend may each be further independently (e.g. separately) defined as applying a whole content, or a series of partial contents, of the components. In other words, every component described herein can be applied as a total amount all at once or in a series of partial amounts over time such that the total amount is eventually applied.

In one embodiment, the cationic polymer is applied to the lignocellulosic pulp simultaneously with the cleaning blend wherein the cationic polymer and the cleaning blend are not mixed with each other during application.

In another embodiment, the cationic polymer is applied to the lignocellulosic pulp simultaneously with the cleaning blend wherein the cationic polymer and the cleaning blend are mixed with each other, e.g. either during application or mixed with each other prior to application.

In another embodiment, the cationic polymer is applied to the lignocellulosic pulp at a different time than the cleaning blend.

In another embodiment, the cationic polymer is applied prior to the cleaning blend.

In another embodiment, the cationic polymer is applied subsequent to the cleaning blend.

It is contemplated that the cationic polymer and the cleaning blend can be added separately in the method. Alternatively, they can be added together. The cationic polymer can be provided independently of the cleaning blend or they can be packaged as a system/product together.

In various embodiments, the technology of this disclosure may be utilized in pulp production, mat formation and drying (e.g. with market pulp), and papermaking. The compositions described herein may be added to brownstock washing and/or bleaching processes. Alternatively, the technology of this disclosure may be added to mat forming processes, mat drying processes, and/or wet storage processes.

In brownstock processing, the dosing point of any of the components described herein can be any point in the process. All points are expressly contemplated herein for use. Typically, the dosing point allows for sufficient mixing and pulp contact time to reduce pitch in the effluent and decrease deposition on equipment.

In bleaching processes, the dosing point of any of the components described herein can be any point in the process. All points are expressly contemplated herein for use. After washing, the composition may be utilized to allow for sufficient time for product mixing and fixing of colloidal pitch.

Alternatively, the technology of this disclosure can be added to the pulp before drying and/or after bleaching, in a high density storage tank, and/or before, during, or after mat formation. In various embodiment, the technology of this disclosure is added to deactivate pitch before a drop in pH.

The technology of this disclosure can also be used for pitch control in papermaking. In various embodiments, the technology of this disclosure is applied to a pulp storage tank, and/or in one or more blend chests, machine chests, leveling chests, etc.

The reduction in content of the at least one hydrophobic contaminant achieved in this disclosure may be calculated using any method known in the art. In various embodiments, pitch reduction is calculated gravimetrically by observing the reductions in organic contaminant weight, by counting pitch defects on finished paper, or by counting pitch particles of certain size.

Pitch particle count is typically based on counting spherical particles in 1 to 10 micron size range with and without chemical treatments. % Pitch count reductions are calculated by taking a ratio of the difference in pitch count without and with chemical treatments over pitch counts without treatment, all multiplied by 100%. A method used for pitch quantification is described in U.S. Pat. No. 10/844,544, which is hereby expressly incorporated herein by reference in its entirety in various non-limiting embodiments.

In various other embodiments, the reduction in content of the at least one hydrophobic contaminant is described as from about 1 to about 100, about 5 to about 95, about 10 to about 90, about 15 to about 85, about 20 to about 80, about 25 to about 75, about 30 to about 70, about 35 to about 65, about 40 to about 60, about 45 to about 55, or about 50, % reduction. Typically, the reduction is described as a reduction in weight but may alternatively be described as reduction in volume or reduction in total number of particles, e.g. pitch particles. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those values set forth above, are hereby expressly contemplated for use herein.

This disclosure also provides a lignocellulosic pulp composition which may be, include, consist essentially of, or consist of a plurality of lignocellulosic fibers, the cationic polymer, and the cleaning blend described above. Each of the above components may be any as described herein and be present in any amount described herein. The terminology “consist essentially of” may describe various embodiments that are free of, or include less than about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 wt %, of one or more cationic polymers that are not those described herein, one or more vegetable oil alkyl ester that are not those described herein, one or more optional vegetable oils that are not those described herein, one or more surfactants that are not described herein, and/or any compounds not described herein or described herein as optional.

EXAMPLES

In the Examples below, cellulose stock solution was used having 0.5% consistency made from bleached Kraft pulp and white water received from a southern US paper mill as well as tap water. The stock solution was furnished either with 20 ppm synthetic pitch or 20 ppm birch pitch extract or eucalyptus pitch extract. Birch and eucalyptus pitch extracts were obtained by extraction from cooked birch or eucalyptus chips. Samples of 0.5% consistency pulp with 20 ppm synthetic or natural wood pitch were treated as described below. The samples were placed in a 50° C. water bath for 30 minutes. After 30 minutes, the samples were removed from the water bath and filtered through 25 micron filter paper. After cooling to room temperature, filtrates were analyzed by Flowcam PV-100 (particle count, size, and shape analyzer from Flow Imaging Technologies).

Filtrate analyses included counting a total number of particles having a particle size of from about 2 to about 10 microns as well as counting a number of spherical particles within the same size range. The number of spherical particles corresponds to the number of pitch particles (or hydrophobic particles in general) within the range of about 2 to about 10 microns. The number of spherical particles (having aspect ratio AR equal to 0.8 or higher, e.g. 0.95) were counted in the samples with chemical treatments and then were compared with the number spherical particles counts in No Treatment (NT) sample (which was furnished with synthetic or natural pitch but no chemical treatment). By calculating the difference in spherical counts and % reductions, the skilled person can assess the efficiency of specific treatment for pitch control. The higher % pitch count reductions means the more efficient the treatment is as a pitch deposition control agent.

Example 1

In Example 1, cationic polymers and various blended compositions were evaluated. The cationic polymers included PolyDADMAC (Polymer A), highly charged cationic polyacrylamide (Polymer B), a polymeric emulsion product with blended PolyAPTAC and cationic acrylamide (Polymer C), and polyvinylamine (Polymer D).

The various Polymers were blended with Formulation E which is an emulsion including soybean oil methyl ester, soybean oil and a combination of non-ionic surfactants to form Formulations A-D. In other words, Formulation E is an example of a cleaning blend of this disclosure, where the amount of soybean oil methyl ester is from about 40 to about 60 wt % actives, the amount of soybean oil is from greater than about 0 and up to about 20 wt % actives, and the amount of castor oil ethoxylate is from about 40 to about 60 wt % actives.

Formulation A is a combination of Polymer A and Formulation E in a weight ratio of actives of 1:4 and is one embodiment of the composition of this disclosure.

Formulation B is a combination of Polymer B and Formulation E in a weight ratio of actives of 1:4 and is one embodiment of the composition of this disclosure.

Formulation C is a combination of Polymer C and Formulation E in a weight ratio of actives of 1:4 and is one embodiment of the composition of this disclosure.

Formulation D is a combination of Polymer D and Formulation E in a weight ratio of actives of 1:4 and is one embodiment of the composition of this disclosure.

Each of Formulations A-D can be described as an inventive contaminant control composition. Formulation E is a control because it does not include a cationic polymer

Polymers A-D were each tested alone at active 0.2 lb/ton dosages to determine % pitch count reduction.

Formulation E was also tested alone at 0.8 active lb/ton dosage to determine % pitch count reduction.

Each of Formulations A-D were also tested at active 1 lb/ton dosages to determine % pitch count reduction.

Pitch count reductions were observed with all evaluations except Formulation D. % Pitch count reductions are summarized in the Table 1 below and FIG. 1 .

TABLE 1 % Pitch particle Treatment red-n (AR 0.95) Polymer A 49.4 Formulation A 41.2 Polymer B 52.5 Formulation B 70.0 Polymer C 44.5 Formulation C 7.6 Polymer D 51.1 Formulation D −10.8 Formulation E 8.1

The data shows that the various cationic polymers were quite efficient in pitch count reductions. % Pitch count reductions were quite high and varied between 44.5 and 52.5%. Formulation E showed a moderate reduction in pitch particles counts of 8.1%.

Moreover, pitch count reductions with the various Formulations were measured to be from −10.8% to 70.0%. For Formulation A, the pitch count reduction was quite high at 41.2% and was comparable to the performance of pure Polymer A used in preparation of Formulation A.

Pitch reductions for Formulation B at 70.0% exceeded the pitch reduction performance of Polymer B at 52.5% and Formulation E at 8.1%. It appears that combining Polymer B and Formulation E to form Formulation B leads to an unexpected boost in performance and results in synergistic improvements in pitch count reductions.

Example 2

In Example 2, various compositions were evaluated. Birch pitch extract was used at 20 ppm levels. All formulations were screened at 1 active lb/ton. Formulations B1 and B2 are blends of cationic polyacrylamide, soybean oil methyl ester, soybean oil and a surfactant packages including castor oil ethoxylate and a C₁₄-C₁₆ ethoxylated alcohol.

Formulation F is a mixture of highly charged polyamine with soybean oil methyl ester, soybean oil and a non-ionic surfactants package as described above.

Formulation G is hydrophobically modified polyaminoamide.

Formulation H is a co-polymer comprising acrylic or (meth)acrylic acid, methyl styrene and styrene.

Evaluations of Formulations B1 and B2 show these formulations to be very efficient in pitch particle count reductions as compared to the other evaluated formulations. Use of Formulations B1 and B2 at 1.0 active lb/ton dosages results in pitch counts declining by 50% or more. This is higher than % pitch reductions achieved with Formulation G. This is also significantly higher than pitch count reductions achieved with Formulations F and H. The results of these evaluations are set forth in Table 2 and FIG. 2 .

TABLE 2 % Pitch particle Treatment, at 1 lb/ton red-n (AR 0.95) NT B1 46.1 B2 54.6 F 11.7 G 31.6 H 3.7

Example 3

Both a cationic polyacrylamide itself (i.e., cationic polymer) and a mixture of soybean oil methyl ester/soybean oil/castor oil ethoxylate (i.e., cleaning blend) have independent pitch reduction properties due to pitch particles fixation on cellulose fibers (by the cationic acrylamide) or due to effective solubilization, stabilization and dispersion of pitch particles in aqueous phases (by the soybean oil methyl ester/soybean oil/castor oil ethoxylate).

A series of seven total formulations (described below) were made by forming a formulation described as Formulation B that includes varying weight percent actives of a charged cationic polyacrylamide emulsion (cationic polymer) described below and varying weight percent actives of the soybean oil methyl ester, the soybean oil, and the castor oil ethoxylate.

Wt % Actives Wt % Actives of Cationic of Cleaning Formulation Polymer Blend Formulation B-0 0 100 Formulation B-16 16 84 Formulation B-32 32 68 Formulation B-50 50 50 Formulation B-68 68 32 Formulation B-84 84 16 Formulation B-100 100 0

The cationic polymer is a high charged cationic polyacrylamide emulsion. The cleaning blend is combination of soybean oil methyl ester, soybean oil and castor oil ethoxylate. The ester is soybean oil methyl ester that is commercially available under tradename Soygold 1000.

The vegetable oil is soybean oil that is commercially available from ADM.

The surfactant is castor oil ethoxylate with HLB of approximately 13.

All of the formulations were tested to determine pitch count reductions at 1 active lb/ton dosage. The results are summarized in Table 3 and FIG. 3 and the results on % pitch particle count reductions (at aspect ratio 0.95) vs a No Treatment sample are summarized in Table 4 and FIG. 4 .

The effects of individual components can be derived from FIGS. 3 and 4 . From the results on % pitch count reductions as set forth in these Figures, it is evident that the effect from a combination of the cationic polymer and cleaning blend is significantly higher than the % pitch count reduction of those compositions independently. This unexpected synergistic effect is found in a wide range of polymer and soybean oil methyl ester/soybean oil/castor oil ethoxylate mixture ratio (from 16 to 84 wt % actives of cationic polymer in the composition).

For example, Formulation B-50 includes 50 wt % actives of cationic polyacrylamide and 50 wt % actives of the cleaning blend. Based on the performance of individual components and their dosages (0.5 active lb/ton each), a skilled person would expect pitch reductions of the mixture to be 49.84% (which is a sum of 5.52% and 44.19%, pitch reductions with Formulation B-0 and Formulation B-100 normalized to their dosages). In fact, % pitch count reduction for Formulation B-50 is 67.24% and is significantly higher than expected from the sum of contributions of individual components. The additional 17.4% is due to the superior and unexpected synergistic boost in pitch count reduction performance. This can be observed in FIG. 4 (as a part of performance bar above the linear line connecting % Pitch count reductions of Formulations B-0 and Formulation B-100). A superior and unexpected synergistic effect is observed for all formulations which are the combinations of the cationic polyacrylamide polymer and the cleaning blends.

TABLE 3 Pitch particle Treatment count (AR 0.95) NT 3479.7 Formulation B-0 3086.0 Formulation B-16 2216.3 Formulation B-32 1573.0 Formulation B-50 1140.0 Formulation B-68  770.3 Formulation B-84  545.3 Formulation B-100  404.3

TABLE 4 % Pitch particle Treatment red-n (AR 0.95) NT Formulation B-0 11.31 Formulation B-16 36.31 Formulation B-32 54.79 Formulation B-50 67.24 Formulation B-68 77.86 Formulation B-84 84.33 Formulation B-100 88.38

Example 4

In Example 4, birch pitch extract was used at 20 ppm level. Two formulations were screened at 0.5 active lb/ton. Formulation B-2 is a blend of cationic polyacrylamide, soybean oil methyl ester, soybean oil and a surfactant, while Formulation B-3 is a blend of cationic polyacrylamide, soybean oil methyl ester and a surfactant (similar to B-2 but without soybean oil in the composition.

Evaluations of Formulations B-2 and B-3 show both formulations to be efficient in pitch particle count reductions even at lower 0.5 lb/ton dosage. Data also indicate that B-3 formulation without soybean oil is even more efficient that the formulation B-2 with soybean oil.

TABLE 5 Treatment, at % Pitch particle 0.5 lb/ton red-n (AR 0.95) NT B-2 27.8 B-3 43.1

Example 5

In Example 5 birch pitch extract was used at 20 ppm level. Four formulations were screened at 0.5 active lb/ton. Formulation B-21 is an emulsion of cationic polyacrylamide, soybean oil methyl ester, soybean oil and a surfactant, while Formulation B-22 is an emulsion of cationic polyacrylamide, soybean oil methyl ester and a surfactant (similar to B-21 but without soybean oil in the composition). Formulation B-23 is an emulsion containing cationic polyacrylamide, soybean oil methyl ester and two non-ionic surfactants (similar to B-21 but soybean oil is replaced with an additional non-ionic surfactant). Formulation B-24 is an emulsion of cationic polyacrylamide, castor oil methyl ester, canola oil and a non-ionic surfactant.

TABLE 6 Treatment, at % Pitch particle 0.5 lb/ton red-n (AR 0.95) NT Formulation B-21 61.5 Formulation B-22 66.5 Formulation B-23 60.2 Formulation B-24 65.5

Evaluations of Formulations B-21, B-22, B-23 and B-24 show that all formulations are very efficient in pitch particle count reductions even at lower 0.5 lb/ton dosage. In this example Formulations B-22 and B-23 do not contain vegetable oil. Their composition comprises of cationic polymer, vegetable oil ester and surfactant(s). Nevertheless, their performance in pitch count reductions is comparable to those of B-21 and B-24, which compositions contain cationic polymer, vegetable oil alkyl ester, vegetable oil and a surfactant.

Example 6

In Example 6 birch pitch extract was used at 20 ppm level. Four formulations were screened at 1.0 active lb/ton. Formulation B-2 is a blend containing cationic polyacrylamide, soybean oil methyl ester, soybean oil and a non-ionic surfactant.

Formulation B-24 is an emulsion containing cationic polyacrylamide, castor oil methyl ester, canola oil and a non-ionic surfactant. Formulation B-25 is an emulsion containing cationic polyacrylamide, canola oil methyl ester, canola oil and a non-ionic surfactant. Formulation B-26 is an emulsion with higher charge cationic acrylamide, castor oil methyl ester, canola oil and a non-ionic surfactant. Formulation B-27 is an emulsion containing higher charge cationic polyacrylamide, canola oil methyl ester, canola oil and a non-ionic surfactant.

TABLE 7 % Pitch particle Treatment red-n (AR 0.95) NT B-2 90.2 B-24 92.3 B-25 92.7 B-26 95.3 B-27 95.7

Evaluations show that all formulations are very efficient in pitch particle count reductions at 1.0 active lb/ton dosage. Example demonstrates that samples are very efficient in pitch count reductions regardless of being blends (B-2) or aqueous emulsions (B-24, B-25, B-26, B-27). Example also demonstrates strong performance regardless of choice of vegetable oil alkyl ester (soybean oil methyl ester, canola oil methyl ester, castor oil methyl ester), vegetable oil (soybean oil, canola oil) and cationic polyacrylamide (regular charge or higher charge). In other words, numerous different vegetable oil alkyl esters, optional vegetable oils, and/or surfactants may be used to achieve superior and unexpected results over what the skilled person would anticipate.

Example 7

In Example 7 birch pitch extract was used in evaluations wherein Formulation E and Polymer B are used, as described above. Formulation E and Polymer B were added together in a first example 7 and also added separately in a second example 7. Testing was repeated at low active dosage (combined actives were 0.5 lb/ton) and at high active dosage (combined actives were 1.0 lb/ton). In one case, Formulation E was added to the 0.5% cellulosic slurry at pH 11 and then the second component Polymer B product was added after 60 minutes mixing followed by pH neutralization to 4.5. In an alternative case both Formulation E and Polymer B are added together at pH 4.5. The pH changes imitated pH declines that can be observed when transitioning from brown stock washing to bleaching and pulp storage conditions. Testing results indicate that both separate additions and simultaneous additions of two separate products results in significant pitch count reductions. Pitch count reductions are significantly higher at higher dosages of Formulations E and Polymer B. There is also an indication that application of both products together resulted in somewhat higher pitch count reductions compared to separate additions, as set forth in the results in Table 8 below.

TABLE 8 Treatment % Pitch count red-n NT Formulation E + Polymer B, 23.9 low dosage added separately Formulation E + Polymer B, 30.2 low dosage added together Formulation E + Polymer B, 49.6 higher dosage added separately Formulation E + Polymer B, 62.9 higher dosage added together

While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims. 

What is claimed is:
 1. A method of reducing hydrophobic contaminants in a pulping or papermaking process, said method comprising the steps of: providing a lignocellulosic pulp comprising lignocellulosic fibers and at least one hydrophobic contaminant; providing a cationic polymer; providing a cleaning blend comprising a vegetable oil alkyl ester and at least one surfactant; and applying the cationic polymer and the cleaning blend to the lignocellulosic pulp to reduce a content of the at least one hydrophobic contaminant in the pulping or papermaking process.
 2. The method of claim 1 wherein the cationic polymer is chosen from polydiallyldimethylammonium chloride, polyamines, polyvinylamines, cationic polyacrylamides, copolymers of polydiallyldimethylammonium chloride and acrylic acid, and combinations thereof
 3. The method of claim 1 wherein the cationic polymer is a cationic polyacrylamide.
 4. The method of claim 1 wherein the cationic polymer is present in an amount of from about 1 to about 51% weight percent actives based on a total weight of actives of a combination of the cationic polymer and the cleaning blend.
 5. The method of claim 1 wherein the cleaning blend is present in an amount of from about 1 to about 90 weight percent actives based on a total weight of actives of a combination of the cationic polymer and the cleaning blend.
 6. The method of claim 1 wherein the vegetable oil alkyl ester is chosen from soybean oil methyl esters, canola (rapeseed) oil methyl esters, corn oil methyl esters, castor oil methyl esters, and combinations thereof.
 7. The method of claim 1 wherein the cleaning blend further comprises a vegetable oil that is chosen from soybean oil, canola (rapeseed) oil, corn oil, coconut oil, olive oil, palm oil, castor oil, and combinations thereof.
 8. The method of claim 1 wherein the cleaning blend further comprises a hydrophobic agent chosen from animal oils, mineral oils, silicone oils, terpenes, natural and synthetic aliphatic hydrocarbons, and combinations thereof.
 9. The method of claim 1 wherein the at least one surfactant is chosen from linear ethoxylated alcohols, branched ethoxylated alcohols, ethoxylated fatty acids, ethoxylated castor oils, ethoxylated sorbitan alcohols, alkyl polyglucosides, ethoxylated glycerides, copolymers of ethylene oxide and propylene oxide, and combinations thereof.
 10. The method of claim 1 wherein a charge of the cationic polyacrylamide is above about 15 mol % and below about 50 mol %.
 11. The method of claim 1 wherein the vegetable oil alkyl ester is present in an amount of from about 20 to about 80 wt % actives, the cleaning blend further comprises a vegetable oil that is present in an amount of from greater than about 0 and up to about 20 wt % actives, and the at least one surfactant is present in an amount of from about 20 to about 80 wt % actives, each based on a total weight of actives of the cleaning blend.
 12. The method of claim 1 wherein a weight ratio of actives of the cationic polymer to actives of the cleaning blend is from about 16:84 to about 50:50.
 13. The method of claim 1 wherein the step of applying the cationic polymer and the cleaning blend to the lignocellulosic pulp is further defined as applying to the lignocellulosic pulp in a pulp mill.
 14. The method of claim 1 wherein the step of applying the cationic polymer and the cleaning blend to the lignocellulosic pulp is further defined as applying to the lignocellulosic pulp in a papermaking machine.
 15. The method of claim 1 wherein the cationic polymer is applied to the lignocellulosic pulp simultaneously with the cleaning blend wherein the cationic polymer and the cleaning blend are not mixed with each other during application.
 16. The method of claim 1 wherein the cationic polymer is applied to the lignocellulosic pulp simultaneously with the cleaning blend wherein the cationic polymer and the cleaning blend are mixed with each other.
 17. The method of claim 1 wherein the cationic polymer is applied to the lignocellulosic pulp at a different time than the cleaning blend.
 18. The method of claim 17 wherein the cationic polymer is applied prior to the cleaning blend.
 19. The method of claim 17 wherein the cationic polymer is applied subsequent to the cleaning blend.
 20. The method of claim 1 wherein the cleaning blend further comprises a vegetable oil. 